Current producing devices, such as transistors, are used in various applications. Techniques, such as the inclusion of one or more electrically conductive shield plates within the transistors, are employed to tailor one or more characteristics or parameters of the transistors to make them more suitable for high power applications. These transistor parameters include, but are not limited to, breakdown voltage (BVdss) and on-state resistance (Rdson). Rdson characterizes the resistive behavior between source and drain terminals of a transistor in the on-state. BVdss characterizes the voltage and current blocking capability between the source and drain terminals when the transistor is in the off-mode. Ideally, transistors used in high power applications are characterized by a relatively high BVdss and a relatively low Rdson, to increase output power and efficiency of the transistors.
Conventional transistor design approaches can result in a trade-off between two or more transistor parameters. For example, for at least some transistor types, the BVdss is proportional to drift length, which is the lateral distance between the gate and the drain. However, an increased drift length and correspondingly higher BVdss causes an undesirably higher Rdson, thereby, decreasing the transistor's effectiveness for high power applications.
Embodiments of the present disclosure are illustrated by way of example and are not limited by the accompanying figures. Elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some elements in the figures may be exaggerated relative to other elements to help to improve understanding of the embodiments.
The apparatus and method components have been represented where appropriate by conventional symbols in the drawings. Some drawings show only those specific details that are pertinent to understanding the embodiments, so as not to obscure the disclosure with details that will be readily apparent to those of ordinary skill in the art having the benefit of the description herein. Also, the functions included in the flow diagrams do not imply a required order of performing the functionality contained therein.